Many kinds of natural fibers are strong and sturdy and have high durability despite repeated washing, compared to synthetic fibers. Also, natural fibers are superior in moisture absorption and warmth-retention properties to synthetic fibers, and are thus hygienic and have a good wearing sensation, and are mainly woven into fabric and widely used as textiles.
However, since natural fibers, having the above advantages, are hydrophilic and thus easily absorb water, fabrics made of natural fibers are readily wetted and may thus shrink. Accordingly, cloth made of natural fabric may shrink due to moisture in the rainy season or easily becomes wet due to rain on rainy days, undesirably deteriorating the wearing sensation.
With the goal of solving these problems, techniques for imparting water repellency to fabrics have been proposed, but include simple coating of the surface of a fabric with a water-repellent coating solution, and thus water-repellent performance may drastically deteriorate over time, which is undesirable.
In this regard, Korean Patent Application No. 10-2012-0052872 discloses a method of preparing a water-repellent fabric. However, this method is applied not to knitted fabrics but to woven fabrics composed of warps and wefts.
Compared to woven fabrics, knitted fabrics have high elasticity, warmth-retention properties and flexibility, and also fit bodies well, are easy to work, and are easy to handle due to wrinkle resistance. By virtue of these advantages, knitted fabrics have been used in socks, gloves, and sweaters for a long time, and the fields of application thereof have gradually expanded to encompass clothing.
As the demand for knitted fabrics, as well as woven fabrics, is increasing, functional knitted fabrics are receiving attention. In this regard, thorough research into knitted fabrics having a water-repellent function is ongoing.
Since knitting yarns are thick and weak compared to weaving yarns, shrinking and entangling of yarns, volume reduction of processed yarns, and changes in tactile sensation should be noted during the production and dyeing of yarns. Taking into consideration the features of knitted fabrics, the present inventors have long studied water-repellent treatment methods suitable for knitting yarns and thus have discovered a method of preparing a knitting yarn having a water-repellent function.